Hydraulic sizing-screen.



F. E! sTEFFY. HYDRAULIG SIZING SCREEN. APPLICATION FILED OUT. 2, 1912.

mggg Patentad. Aug. 19, 1912 i SHEETS-SHEET 1.

L2 wzmmsws;

I N VEN TOR.

F. E. STEFFY.

HYDRAULIC SIZING SCREEN.

APPLICATION FILED 00T.2, 1912.

Patented Aug.19,1913.

4 SHEETS-SHEET 2.

WITNESSES:

APPLIGATION FILED OGT.2,1912.

Patented Aug. 19, 1913.

4 SHEETSSHEET 3.

WITNESSES:

F. E. STEFFY. HYDRAULIC SIZING SCREEN.

APPLICATION FILED 001. z, 1912 11 55g Patented Aug. 19, 1913.

4 SHEBTB-SHEET 4.

l .z; WITNESSES: 5 l 0 INVEMTOR.

Q UNITED STATES AT 1 FlC..-

FRANK E. STEFFY, OF GREAT. FALLS, MONTANA.

HYDRAULIC SIZING-SCREEN.

Specification of Letters Patent.

Patented Ari 19,1913.

Application filed October a, 19-12; Serial No. 723,558.

To all whom it may concern.

Be it known that I, FRANK E. S'rErrY, citizen of the United States,residing at Great F alls, in the county of Cascade and State of Montana,have invented certain consists in the novel detailsof construction morefully set forth in the specification and pointed out in the claims. a i

In the drawings, Figure 1 is a middle vertical longitudinal section ofthe apparains, with parts in elevation; Fig. 2 is a vertical transversesection on the-line 2-2 of Fig. 1, partsbeiug broken away; Fig. 3 is ahorizontal section on the zig-zag line 3-3 of Fig. 1, parts beingbroken; Fig. 4- is ahorizontal sectional detail on the line 4-4 of Fig.2; Fig. 5 is a middle vertical transverse cross'section through thecocentric and theupper cross-head supported thereby on the line 5-5of-Fi'g. 2, showing the normal vertical position of the hanger- 'roilsuspended from said cross-head, the drive-shaft being in side elevation;Fig. '6

is a similar sect-ionshowing the eccentric partly turned, and thecross-head and-slide thereof, and the hanger-rod, partially tilted fromtheir normal position in response to thchorizontal movements imparted tothe screen-tray to which the lower end of the hanger-rod is coupled;Fig' 7 is an enlarged plan or face view of the quadrant and sliding shoeforming the support for-the swivel which carries the upper end of thelink or end-motion arm, parts being broken; Fig. Sis a cross-section onthe line 8-8 ofFtg. 7 with the link arm and controlling springv thereforshown dotted; Fig. 9 is a diagrammatic view illustrating the motionsimparted.

ofthe mill. The material which passes.

ident fied with this fine material.

through the mesh is then sized and classified by screens and hydraulicseparators. The prevailing sizing screen does not work efficiently asdesirable, and is open to the objection in that it does not segregatefrom the coarser particles, the exceedingly fine grains and matter knownas slime (.when mixed with water) a portion of which is carried ofi withthe oversize or material too coarse to pass through the mesh of thescreen. In any operation of sizing by means of screens, inefficiencyresults from increased cost of screening, a large number of screensbeing required, and the material necessitating frequent rehandling. Notonly does such a-method impose excessive wear on the screens and othermachinery, but much valuable nuneral is lost in the form of slimeorfines, being carried away by the 'very fine material.

It is thcrefore the object of my invention to increase to a maximum theefficiency of screen-slung, this-being accomplished by associating withthe screening action a .hy-

draulic separation which not only com pletely separates the individualparticles from one another, but washes free the adhering partlcles ofslime or fines which, 1n

conjunction with the movements imparted to the screen, assist in keepingthe screen apertures-open. The oversize thus becomes thoroughlydeslimed, permitting of independent concentration of the slimes andli'eheeihe recovery of the bulk of the'valnes In my invention thedeslimed oversize is also completely dewatered as it leaves the screen,

being thus brought to a condition favorable to the specific mode oftreatment or concentration adopted for relatively coarser material.

The advantages of thepresent invention will be apparent-from a detaileddescription thereof, which is as follows Referring to the drawings, andfor the present to Figs. 1 to 8 inclusive, 1 represents a tank madepreferably of wood, the same being divided into a series of compartmentsor hutchcs a, b, c, (three here being shown) by partitions w, w.Positioned within the tank is the screen tray 2 provided with a forwarddownwardly inclined extension 2 which projects through and beydnd thefront terminal wall 10 of the tank, said wall being made of twosectionsdisposed one on either side of said extension (Fig. 1). The tank 1 isreinforced by buckstays 3 connected at the top by cap-pieces 4 whichsupport the shafting. No novelty however, is attached to such featuresas they are well understood in the art. The tray 2 carries thehorizontal screen 5 deposited on a wooden frame of transversely disposedribs r forming the bottom of the tray, the sides of the screen beingclamped tovthe frame by means'of stringers 6 forced against the screenby means of wedges 7 driven between them and the lugs or plates 8secured to the sides of the tray 2. The extension is provided with aninclined screen 5 secured in position in any mechanical manner, a bottomguard or apron 9 being secured to the front of the extension to directthe water into the compartment 0. The several compartments are'providedwith discharge plugs 10 having an inwardly flaring passage h (Fig. 1 The forward terminal of the screen-tray 2 proper is connected tothe wall w by means of flexible diaphragm or hinge 11 of leathery rubberor equivalent flexible sheet material, said diaphragm preventingintercommunication between the compartments 1) and c. The diaphragm iscofivexed toward the compartment 6 and permits of a combined verticaland horizontal reciprocation being imparted to the tray 2 and thescreens 5,5, as will be more fully hereinafter described. Mounted overthe a rear end {of the "tank 1 is the feed-box B (-preferably'lincd withiron 2') from which lead a series of transversely disposedc'ast ironspouts 12 discharging the pulp directly over the rubber lining 13 withwhich the rear end of the tray 2 is'provided.- Below the plugs 10 arearranged launders or boxes L in which the material discharged from'therespective compartments a, b, 0, is caught.

Under the present invention, a reciprocating movement "must be impartedto 'the screen jbotlivcrtically, and. at the sametime horizontally, theresultant of these motions .not only serving to cause the fines to pass'14: at the sides of the-'screen-tray are the lower ends of th ,(twopairs of) hanger rods lfiavl ose upper screw-threaded pore tions arepassed through the ends o-f'the' pairs of cross-heads 16, 16, suitablejamnuts n being provided Where convenient to allow for proper fasteningand adjustment of the parts (Fig. 2). The lower ends of the hanger rodshave steel-bushed e es (in ,fillrn supplied *with a'brassbushingl, eachpair'of rods (on opposite sides of the tray) having a common transversebolt 17 passed through the eyes and the strap-ends between which theeyes of the rods are re* ceived. As previously stated, the cappieces 4:support the shafting, each cap-piece being provided with a bearing 18,for the support of the drive-shaft S operated by the belt-pulley P (orequivalent manner).

The shaft is provided with any conventional form of adjustable eccentric19 the strap or ring 20 of which operates betweenthe crossheads 16, 16,a slide 21 adapted to longitudinally traverse the cross-head 16 beinginterposed between the eccentric strap 20 and connection with thecross-head 16) recipro,

eating back and forth along the cross-head 16 to conform to thehorizontal travel of the strap 20 as'it is being drivenfby theeccentric; Theeccentric being adjustable, it follows that the degree ofeccentricity may be varied by the'operator whereby a greater orle's'svertical throw may be impartedto the cross-heads and hence to thescreen-tray.

Any standardim'a ke of adjustable eccentric may be employed asalr'eadystated.

It will be seen from the'drawings that the contacting. or engagingsurfaces between the strap 20 and slide 21 are respectively convex andconcavefollowing the surface of a sphere whose center lies on' theaxisof the shaft S. This curved surface of contact'be- 7 or ring 20' in aplane atrightangles tothe plane ofrotation of. the eccentricKIfig. 6),

and hence permitting the hanger-rods andthe cross-heads to which t-heyare coupled, to oscillate about the center of the joint aforesaidfwhichcenter as previouslystated lies on theaxis of the shaft S. Theoscillation just referred to'will obviously beina plane parallel to theaxis :of the shaft and since the scrcen-tray is suspended "from" thehanger-rods to which thisoscillation may be imparted, it fol lows thatthe tray may reciprocate not only yertical 1y but at the same timeho1-izo1itally, 'sa id horizontal movement being necessarilylongitudinal. with the tray because parallel to the shaft S. T he-nie(-,hanism by which' this horiy'r'intal movement'is imparted to thescreen-tray while the latter is reciprocating 'vertioally may vary, thefollowing being an example :Bolted to the inner faces 01f the rearextensions 1 of the in Fig. 8,, to which a cap-plate 24: may be secured,the heads of thqzbolts t by which .the parts are secured spa ning thesides of the slot. The shoe and p-plate are suitably cored to receivethe trunnions m, m, of a cored swivel 25., the swivel rotating in aplane parallel to the face of the quadrant. Through the opening D of theswivel freely passes a forwardly anddownwardly inclined link orend-motion arm 26, whose lower end is pivotal l-y secured between theears 0 of the castings 27 bolted on opposite faces of the sides of thescreen-tray, the link being pro vided with jan1-nuts n, n, for changingthe efl'ective len 11 thereof, a coiled compression spring 28 einginterposed between the swivel 25 and the nuts n for purposes not only ofcushioning the jar of the shake of .thescreen, but for maintaining asubstan- -tiall fixed length for the link once the same has eon-adjustedby the proper shifting of the jam-nuts n, n. It will be seen that byshitting the shoe 23 along the quadrant and adjusting the efiz'ectivelength of the link or end-motion arm 26, any variety of horizontalstrokes for the screen may be effected; and since the vertical strokesmay likewise be adjusted bya proper adjustment of the eccentric, thecharacter and degree of reciprocation to be imparted to the screen maybe varied at pleasure depending on the nature and size of material to besized or treated.

As the screen-tra reciprocates vertically under the action 0 theeccentrics 19, it is apparent that the links 26 coupled as they are tothe tray, will be oscillated in a vertical plane; but since the linksoscillate along arcs of circles whose centers are substantially on theaxes of the swivels 25, the screen-tray will be reciprocatedhorizontally through a distance represented by the hori-' zontalcomponent of the chord of the are described by the lower end of eachlink, the vertical component being necessarily responsive to theverticalthrow resulting from the action of the eccentrics. It followsthat by virtue of the links or end-motion arms 26, the motion of thescreen is resolved into an upward and forward stroke with a risingmovement of the screen, thereby throwing the feed or pulp forward andcausing it to travel rapidly over the screen toward the dewateringextension2'. With a falling of the screen themotion is downward andrearward thereby giving the particles suspended in the water an the tank1 opportunity to fall ontofresh portions of the screen when they are'mi'shed forward with the next or one direction) in hollow bearings 30of suitable castings 31 bolted to a longitudinal timher or stringer 32spanning the cap-pieces 4.

The pulp flows from the feed-box through the spouts 12 onto the rubberdistributor lining 13 whence it flows in sheet form over the screen 5,the screen being just Submerged or close to the surface of the water inthe tank 1 when it reaches the limit of its upward and forward stroke.In Fig. 9 I have shown diagrammatically and to the best advantage theoperation of the screen. As the eccentrics 19 reciprocate the hangerrods15 vertically, the link-arms 26. will cause the screw-tray 2 and screen5 (and the parts 2, 5) to oscillate horizontally, the resultantfollowing substantially the chord o of the are 3/ described by thelowcnend of the arm 26. The chord 1) forms the hypotenuse of a rightangled triangle the perpendicular p of which represents theeffectivevertical double stroke or throw to which the screen is subjected,thebase in representing the horizontal component or the total distancetraversed by the screen horizontally for a given inclination of thelink-arm 26. By shifting the center of oscillation of the link-arm, amere matter of adjustment of the shoe 23 along the slot .9 of thecasting 22 and by varying the effective length of the link-arm and byvarying the effective eccentricity o. the eccentric, it is clear thatany desired shake or reciprocation may be imparted to the screen. Byreducing the throw of the eccentric 19, the vertical component of theinclined path imparted to the screen will be reduced; by lengthening thearms 26 the greater will be the horizontal component of the pathdescribed by the screen; by lowering the centers of oscillation of thelinkarms the. less will be the horizontal displacement of the screen; byraising the centers'lef oscillation of the link-arms the.

greater will be the horizontal component of the inclined path orreciprocation of the screen. These are matters quite obvious from thediagrammatic illustration in F 9 in which the link-arm is shownsubstantially at forty-five degrees to the horizontal when at the centerof its arc of oscillation. A shifting of its, center of oscillation or achange in its eflective length will at once,

obviously affect the directionof the are described by the lower endthereof, or thatglSO 25 andthe particle 35 :Water in the y practicallyat all times submerged) and Work their waythrough the meshesoraperfinally settling through 55 size thus coupled to the screen-tray andhence vary the horizontal throw of the screen for any given verticalreciprocation ofthe latter.

The vertical reciprocation or component on the other hand-may be changedby proper adjustment of the eccentric 19. Referring again to Fig. 9, aparticle of ore resting on the screen at the point. 0 when the screen isdown, will be elevated to the point e as the 0 screen is raised.

When next the screen is depressed said particle will be left behind(because suspended in the Water in the tank) and precipitate onto thescreen to the point 0?; when the screen is next elevated thep art-icleis raised to the point toand with the next depression of the screen theparticle drops to the point 0 and so on). .Since the particle willalways. fall substantially vertically whereas the screen-falls andrisesdiagonally,

it follows that the'particle'will be progressivelyadvancedforward alongthe screen 5 until-it reaches the inclined screen 5 Where it isdewatered, the Water flowing through -the;screen 5' intothe emptycompartment '4', discharging over the edge of the extension-screen 5,and caught me suitable receptacle (not shown)., The path ofthe particleas just described is the 001m .mion path described by all particleswhich :are too large to pass through the screen (5),

@such particles collectively constituting the oversize. In thereciprocations of the screen the undersize or fine particles or slimebe- ;come detached from the oversize by the tank (in which the screen isturesof the screen, thewater to the bottom of the compartments \a, b,whence they are discharged a stream of slime throughtheplugs 10. Thepresence'ot'. the water in-the tankl, and the specific character ofreciprocation or shake im- -parted to the screen while submerged has 5the efiect of not only advancing forward the oversize along the screen,but in desliming .the oversize, the fines all passing, through themeshes of the screen. beneath the screen and settlingto the bottom oftheir respec- .tive compartments. The deslimed oversize finally iswoikedoff the extension screen 5 "Where it is dewatered, the water drainedtherefrom being caughtin the empty compartment c asalready described.The overdeslimed .and dewatered may be readily concentrated because nolonger interfered with by adhering slime particles;

and the slimes on the other hand mayvbe separately treated. without lossin vahles. 0 This is a decided advantage flowing from the use of myinvention. In Fig.,1;the water level in the tank 1, is represented bythe dotted line as being a shade above the plane reached by the screenwhen at its highest 5 elevation.

As stated above, the swivel 25- constitutes but one form of pivotalconnection for the fixed or fulcrum endof the link-arm 26; and in Figs.10 andfill'l show 'a modified form of shoe 23 provided with lobes E forthe passage of suitable securing bolts (such as 't) by which theshoemaybe-adjusted along the'slot s of the quadrant 22. "The shoe 23 isprovided With a passageway D "having'inwardly convex walls; that is tosay, cylindrical Walls gradually flaring outwardlv' 1n both directionswhereby thelink 26 with its upper endsupportedinsaid' pas- 1 sage way Dis free to'oscillate the necessary distance while performingits'function, as an end1no tion arm (see dotted positions in Fi s. l0, l1).Any other'equivalentform of l in connection may be substituted. .Shouldthe Water accompanying from" the box B be insniiicient to maintainthe-contents of the tank'l at the proper level/(m), additionalwatenmaybe introduced through pipes W entering the side of the tank. In thefinal dewatering of the oversize onthe screen 5', not only water,butsome shine and otherjmaterial will .pass through this s'creeninto theempty compartment 0; and-if the slimes have'sufiicient value they maybe-savedand subsequently suitably treated; otherwise'thecontent-s of.

I the'compartment c' are discarded.

lflaving'describ d my inve'tion whatI 'claimis I 1; In combination witha'Iwater-tank, a screen disposed adjacent the surface of the water inthe tank, means forconducting a pulp sheet over the screen, 1neansfor1mparting to a downwardly and outwardly inclined- .screen-extension,carried by the screen and projecting beyond and out of the 'deslimingrater-body, and a manner for catchingtfhe water and slime passed throughthe extension, the latter having-an edge-over which the-pulp combinedhorizontal" and "vertical reciprocations to the screen beneath the sur-.the oversize may discl'iai'ge 'to' a point be.

yond the container.

screen,positioned adjaeent'to 'thejsurfaee of I thmavater indhetank,means "for dischargmg pulp Ill l|(t'-i; 'i -)l'm onto the screen,

means For imparting" properreciprocationS -to the screen b neath thesurface of the Water in the tank for advancing the oversize of the pulpin-a given direction along the screen, a Water-tight flexible memberconnecting the screen to the tank, and a perforated member forming anextension of the screen for dewatering the oversize at a point beyondthe flexible connection.

4. In combination With a Water-tank, a screenrpositioned adjacent to thesurface of the water in the tank, means for delivering pulp onto thescreen, means for imparting simultaneous vertical and horizontalreciprocations to the screen beneath the surface of the Water in thetank, Whereby'the solid material of the pulp is advanced along thescreen in a given direction, a Water-tight flexible member connectingthe screen to the tank, an empty compartment beyond the flexible member,a screen extension overhanging said empty compartment and rece ng theoversize advanced along the sub merged portion of the screen anddischargr ing' said oversize at a point beyond said en' ptycompartn'icnt, the latter catching the uter drained from the oversizeaccumulating on the screen extension.

5. In combination With a tank filled with Water, a shaking screensubmergible beneath the surface of the Water, a Water-tight flexibleconnection between the screen and a Wall of the tank, an emptycompartment adjacent the wall to Which the flexible connection issecured, and a screen devvatering extension above the flexibleconnection projecting over the empty compartment.

In testimony whereof I aflix my signature, in presence of two Witnesses.

FRANK E. STEFFY.

Witnesses l v S. ll Cmxsn, T. P. ConoonAN.

